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Human Electrical Muscular Incapacitation and Effects on QTc Interval
John A Gibbons1, Andrew J Mojica2, Mark E Peele3
1Air Force Research Laboratory, Bioeffects Division, Airman Systems Directorate, 4141 Petroleum Road, Bldg. 3260, Fort Sam Houston, TX, 78234.
Journal of Forensic Sciences
|April 19, 2017
Summary
Human Electrical Muscular Incapacitation (HEMI) may alter cardiac electrical activity. HEMI exposure can lead to QTc interval changes, including prolongation, potentially increasing the risk of ventricular tachycardia.
Area of Science:
- Cardiology
- Forensic Medicine
- Electrophysiology
Background:
- Human Electrical Muscular Incapacitation (HEMI) is employed to control combative individuals.
- Concerns exist regarding potential cardiac electrical disturbances following HEMI application.
- Previous research suggests a link between HEMI and fatalities, possibly due to cardiac events.
Purpose of the Study:
- To investigate the impact of HEMI exposure on the QTc interval.
- To determine if HEMI causes significant changes in cardiac electrical activity.
- To assess the risk of arrhythmias associated with HEMI-induced EKG alterations.
Main Methods:
- Electrocardiogram (EKG) recordings were obtained from 24 participants before and after a 5-second HEMI exposure.
- EKGs were analyzed by a blinded cardiac electrophysiologist to calculate the corrected QT (QTc) interval using the Bazett method.
- QTc prolongation was defined as >430 ms, with a 30 ms threshold for QTc lengthening.
Main Results:
- Five participants exhibited QTc prolongation after HEMI exposure.
- Six participants showed a QTc lengthening exceeding the 30 ms threshold.
- One individual experienced QTc prolongation over 500 ms, a level associated with increased risk of multifocal ventricular tachycardia.
Conclusions:
- HEMI exposure can induce changes in EKG parameters, specifically affecting the QTc interval.
- A subset of individuals exposed to HEMI demonstrated significant QTc prolongation.
- These findings suggest a potential risk of cardiac arrhythmias, including ventricular tachycardia, following HEMI application.